ES2713036T3 - Article covered in blue with low emission coating - Google Patents

Abstract

A coated article that includes a multilayer coating (3) supported by a glass substrate (1), the coating (3) comprising at least the following layers from the glass substrate (1) outward: a first layer (5) that comprises silicon nitride; a first contact layer (7); an infrared (IR) reflective layer (9) located above and directly in contact with the first contact layer (7); a second contact layer (11) located on and in direct contact with the IR reflecting layer (9); a dielectric layer (13); characterized in that the coated article has a reflective color value of the glass side b * of -15 to -25, wherein the first layer (5) comprising silicon nitride has a thickness of 72.5 to 110 nm, and wherein the coated article has an a * value of reflective color of the glass side of -4 to + 4 and an RgY value of visible reflectance of the glass side of 15 to 30%, where the first contact layer (7) comprises Ni and / or Cr, the infrared (IR) reflective layer (9) comprises silver, the second contact layer (11) comprises Ni and / or Cr and the dielectric layer (13) comprises silicon nitride, and wherein the coating (3) includes only one Ag-based layer that is the IR reflective layer (9), and wherein the first layer (5) comprising silicon nitride is in direct contact with the glass substrate (1), and wherein the coating (3) consists practically of the mentioned layers.

Description

DESCRIPTION

Blue coated item with low emission coating

The present invention relates to coated glass articles suitable for an insulating glass window unit (IG) or another type of window unit, the glassware including a coating designed to allow the coated article to have a color reflective blue on the side of the glass. In particular, the thicknesses of the layers in the coating are designed to allow this blue color to be produced. The coated article may or may not be heat treated in various illustrative embodiments of this invention.

BACKGROUND AND SUMMARY OF THE INVENTION

Coated articles and IG window units using the following coating are known: glass / SiN / NiCr / Ag / NiCr / SiN. For example, see patents US-6,605,358, US-6,730,352 and US-6,802,943. While these coated articles provide good results in many applications, sometimes their color characteristics are not desired.

Reference document US-5,800,933 relates to a system of low-emission spray-coated layers for automotive and architectural purposes of the basic type Si ³ N ⁴ / NiCr / Ag / NiCr / Si ³ N ⁴ improved by a base of TiC ^{> 2} or by using stainless steel in Si ³ N ⁴ layers, or both.

In addition, EP-0 722 913 relates to a coating system of low-emission glass with a double layer of silver and insulating glass units made therefrom.

EP-0 567735 A1 suggests a high performance, durable, low emission glass that exhibits a visible transmittance of about 80% or more, a hemispheric emissivity (Eh) of about 0.13 or less and a normal emissivity (En) of approximately 0.10 or less.

WC 01 66 483 A1 discloses glass articles coated with low-emission glass comprising a glass substrate and a multi-layer coating on a surface of the glass substrate. The coating includes a layer of transparent dielectric material adjacent to the surface of the glass substrate, and the respective layers of nichrome of nichrome and silver, each formed by spray coating on the glass substrate in a nitrogen-containing atmosphere. .

WC 03 022 770 A1 suggests a thermotratable coated article that includes an infrared (IR) reflective layer, wherein the illustrative stack of layers includes: glass / Si ³ N ⁴ / NiCrNx / Ag / NiCrNx / Si ³ N ⁴ .

WC 0140 131 A2 refers to a glass laminate or heat-settable and compatible IG unit employing a layer system and including a layer of silver sandwiched between nichrome layers and subsequently Si ³ N ⁴ layers.

EP-1 446 364 2 suggests a coated article that includes a coating supported by a substrate, the coating includes a metal nitride or thin metal contact layer located directly between, and in contact with, an infrared (IR) reflective layer and an oxide barrier layer.

In particular, a fairly strong blue color is sometimes desired (eg, a reflective color on the side of the glass). Typical glass / SiN / NiCr / Ag / NiCr / SiN coated articles do not provide this strong blue coloring on the glass side along with the desired solar characteristics. For example, prior to the heat treatment, Example 1 of US-6,605,358 with a glass / SiN / NiCrN / Ag / NiCrN / SiN stack provides a reflective color a * on the glass side of -0.96 and a reflective color b * on the glass side of -7.92. These color values change slightly with the heat treatment (heat treatment - HT). Unfortunately, the b-value of -7.92 is not blue enough for certain applications. In view of the foregoing, the object of the invention is to increase the accessible area of possible values of reflective color of the glass side in the art for a coated article capable of providing a combination of good solar control characteristics.

This object is solved by a coated article according to claim 1.

Surprisingly it has been found that a desirable blue color can be obtained, in combination with good solar characteristics, by adjusting the thicknesses of the layer (s) in the coating.

According to the invention, a coating is provided which provides a b * reflective coloration on the glass side of about -15 to -25, more preferably of about -16 to -23 (before and / or after an optional heat treatment), in combination with a reflective coloration on the glass side of about -4 to 4, more preferably about -2 to 2. Good solar control characteristics can also be achieved (e.g., laminar strength and / or sufficient emissivity). low). The combination of these desirable characteristics can be made by thickening the lower dielectric layer, while possibly providing a thicker upper dielectric layer in certain illustrative cases.

The coated articles according to this invention can be used in the context of insulating glass window units (IG), monolithic windows, or in other suitable applications in different cases.

According to the invention, there is provided a coated article having a glass / SiN / NiCr / AG / NiCr / SiN stack where the lower layer including silicon nitride has a thickness of about 72.5 to 110 nm, more preferably, approximately 80-95 nm. The top layer including silicon nitride can have a thickness of about 30-70 nm, more preferably about 48-65 nm. These thickness ranges used in combination allow to obtain a significant blue coloration desirable in certain illustrative embodiments of this invention.

According to the invention, there is provided a coated article that includes a multilayer coating supported by a glass substrate, the coating comprising at least the following layers of the glass substrate outwardly: a first layer comprising silicon nitride; a first contact layer comprising Ni and / or Cr; an infrared (IR) reflective layer comprising silver located on and directly in contact with, the first contact layer comprising Ni and / or Cr; a second contact layer comprising Ni and / or Cr located on, and directly in contact with, the IR reflecting layer; a second layer comprising silicon nitride on the glass substrate located on at least the IR reflecting layer, the contact layers and the first layer comprising silicon nitride; and wherein the first layer comprising silicon nitride has a thickness of about 72.5 to 110 nm in thickness, and wherein the coated article has the following reflective color values on the glass side: a * -4 to 4 , and b * from -15 to -25.

Brief description of the drawings

Figure 1 is a cross-sectional view of a coating on a substrate according to this invention.

Figure 2 is a cross-sectional view of an insulating glass unit (IG) including the coating of Figure 1.

Detailed description of certain illustrative embodiments of the invention

This invention relates to a coated article that includes a coating supported by a substrate. The coating is provided directly on, and in contact with, the underlying substrate. In certain illustrative cases, the coated articles according to this invention can be used in a window unit (eg, IG window unit, or in any other type of suitable window unit), and provide visible transmission (T ^vis ) , visible side glass reflectance (R ^g Y), transmission color (a * and / ob *), and / or reflective color on glass side (a * and / or ob *) desirable. In the embodiments of this invention, the reflective blue color of the glass side with respect to a * and b * is especially important.

Figure 1 illustrates a coating 3 according to this invention, supported by the glass substrate 1. The substrate 1 is glass, such as sodium-calcium silica glass, borosilicate glass or the like. As for the color of the glass, the substrate 1 may be transparent, green, bronze, blue green, gray, or any other suitable color in different embodiments of this invention, and with a thickness preferably of about 1.0 to 10.0 mm , more preferably from about 1.0 mm to 6.5 mm (eg, 4 to 6 mm thick).

The coating 3 shown in Fig. 1 includes, from the glass substrate 1 outwards, layer 5 including silicon nitride, lower contact layer 7, infrared reflecting layer (IR), upper contact layer 11. and upper dielectric layer 13. The "contact" layers 7 and 11 are each in contact with the IR reflecting layer 9. The infrared (IR) reflective layer 9 can be made of, or include, silver (Ag), or alloys thereof.

However, metallic or practically metallic Ag is the material of choice for the IR reflective layer 9 in the embodiments of this invention. The IR reflective layer allows the coating 3 to have good solar control characteristics such as sheet strength and / or low emissivity.

Both contact layers 7 and 11 are of, or include, Ni and / or Cr. Both contact layers 7, 11 are of, or include, nickel (Ni), chromium (Cr), or a nickel-chromium alloy. The Ni, Cr, or NiCr may be nitrided (eg, NiCrN ^x ) in certain embodiments of this invention, which favors improving the optical stability of the coating in a heat treatment, such as thermal tempering. It will be appreciated therefore that one or both of the contact layers 7 and 11 may comprise nickel oxide, chromium / chromium oxide, a nickel alloy oxide such as nickel-chromium oxide (NiCrO ^x ), a nickel alloy nitride such as nickel-chromium nitride (NiCrN ^x ), or a nickel alloy oxynitride such as nickel-chromium oxynitride (NiCrO ^x N ^y ). When one or both of the contact layers 7 and 11 comprise NiCr or NiCrN ^x , Ni and Cr can be provided in various amounts, such as in the form of nichrome of about 80-90% Ni and 10-20% Cr by weight . In other embodiments, the Metallized targets used in layer (s) 7 and / or 11 may be 50/50 Ni / Cr, 60/40 Ni / Cr, 70/30 Ni / Cr or any other suitable weight ratio. An illustrative vacuum metallizing objective to deposit these layers includes not only the SS-316 which consists practically of 10% Ni and 90% of other ingredients, mainly Fe and Cr, but potentially also the Haynes alloy 214, (p. See, for example, US Pat. No. 5,688,585). Optionally, one or both of the contact layers 7 and / or 11 may be of gradual oxidation and / or nitrogen in different embodiments of this invention so that they are more metallic closer to the IR reflecting layer and less metallic in addition to the IR reflective layer 9. The contact layers 7 and 11 may or may not be continuous in different embodiments of this invention, depending on their respective thicknesses.

Both dielectric layers 5 and 13 are of, or include, silicon nitride (eg, Si ³ N ⁴ stoichiometric or any other non-stoichiometric form of silicon nitride). The silicon nitride can be doped with Al, stainless steel or similar. One or both dielectric layers 5, 13 may include silicon oxynitride, silicon oxide or any other suitable dielectric material.

In certain illustrative embodiments, the dielectric layer 5 may comprise a silicon-rich (Si-rich) form of silicon nitride (ie, SixNy where x / y may be from about 0.76 to 2.0, more preferably from about 0.80 to 1.5 and most preferably from about 0.80 to 1.3). Making layer 5 silicon nitride non-stoichiometric by increasing its Si content causes the refractive index of layer "n" and the extinction coefficient "k" to increase (eg, in the range of 350-550 nm ). In particular, increasing the Si content in layer 5 of silicon nitride (ie, making it Si-rich) causes the layer to have a refractive index "n" (at 550 nm) of 2.15 to 2.6 , more preferably from 2.2 to 2.5, and most preferably from 2.35 to 2.45 (compared to a "n" refractive index of 2.05 for stoichiometric Si ³ N ⁴ ). As stated above, making layer 5 rich in Si causes "n" and "k" to increase; however, care should be taken to ensure that "k" does not increase too much. In particular, if "k" becomes too high (eg, greater than 0.07), an undesirable brown color may appear in certain cases. Therefore, it is sometimes desirable not to make the silicon nitride layer 5 too rich in Si. In certain embodiments of this invention, the content of Si in layer 5 of silicon nitride is raised (to make it non-stoichiometric) to such an extent that the extinction coefficient of layer "k" (at 550 nm) is 0. to 0.07, more preferably from 0 to 0.06, even more preferably from 0 to 0.05 and most preferably from 0.0001 to 0.05.

According to this invention, the coating 3 can include at least the layers listed below, from the glass substrate outward (illustrative thicknesses are given in units of nm):

Table 1: Example of coating

It has been found that the increased thickness of the lower silicon nitride layer 5 is especially useful to achieve the desired reflective blue coloration of the glass side of the coated article, when the other layers are of thickness used to obtain the desired solar control characteristics. . In certain embodiments of this invention, the thickness ratio of layer (5) / layer (13) is from about 1.4 to 2.0, more preferably from about 1.5 to 1.9, and most preferably from approximately 1.6 to 1.8. In combination, the thicknesses used above allow to obtain good blue color and good optical and solar color characteristics that will simultaneously provide the coated article before and / or after the thermal treatment.

In an illustrative non-limiting embodiment, the silicon nitride base layer 5 has a thickness of about 85 nm, the lower layer 7 including NiCr has a thickness of about 6 nm, the IR-reflective layer 9 with Ag base has a thickness of approximately 9 nm, the upper NiCr contact layer 11 has a thickness of approximately 6 nm, and the silicon nitride coating layer 13 of a thickness of approximately 50 nm.

Fig. 2 illustrates part of an IG window unit including the coating 3 of Fig. 1. As shown in Fig. 2, the coated substrate 1 is preferably coupled (after the HT in certain cases) to another substrate (glass or plastic) 20 by means of at least one separator and / or seal 22 to form an IG window unit. The space or gap 24 between the opposing substrates may or may not be evacuated at a pressure lower than atmospheric. In addition, the space or void 24 between the substrates may or may not be filled with a gas (e.g., Ar).

Thermal treatment (eg, thermal tempering) is optional. In certain illustrative embodiments, the coated article can be thermally treated, which often requires heating the coated substrate at temperatures of 500 ° C to 800 ° C (more preferably, about 580 to 750 ° C) for a sufficient period of time, p. eg, from 1 to 15 minutes, to achieve the desired result, p. eg, thermal tempering, bending and / or thermal reinforcement).

According to this invention, the articles coated herein have the following optical characteristics in monolithic form (ie, not in the form of an IG unit), before any optional thermal treatment, and measured with respect to III.C, observer of 2 degrees Note that the characteristics a * and b * that follow are for before and / or after the thermal treatment of the monolithic coated article.

Table 2: Illustrative Characteristics (Monolithic) (Before / After HT)

Most Preferred General Characteristic Maximum preference T ^vis (or TY) (transmissive): 30-60% 35-55% 37-50% a * t: -7.0 to 1.0 -6.0 to -4 -4.5 a -0.5 b * t: -2.0 to 5.0 0.5 to 3.5 0.5 to 3.5 R ^g Y (glass side): 15 to 30% 15 to 25% 17 a 23% a * _g : -4.0 to 4.0 -3.0 to 3.0 -2 to 2 bb * _g :: -15 to -25 -16 to -23 -17 to -22 R ^f Y ( side of the film): 6 to 18% 8 to 16% 10 to 14% a * f: -10 to 20 -5 to 18 5 to 15 b * f: -10 to 20 -5 to 18 5 to 16 Resistance of the sheet before <= 11 ohms / square <= 10 ohms / square <= 9 Q / square HT:

Resistance of the sheet after <= 9 ohms / square <= 8 ohms / square <= 7 Q / square L H ITT

From the very negative reflective b * coloration on the glass side, in combination with a reflective coloring on the rather neutral side of the glass, it can be seen that a good reflective blue color is obtained. This was surprisingly achieved as explained above by adjusting the thickness of the layer (s) of the coated article according to this invention.

In certain illustrative embodiments, the monolithic coated article can be used in an IG window unit as shown in Fig. 2 of the present application, for example. In such IG embodiments, the IG window unit may have a visible transmission of about 25% to 55%, more preferably about 30% to 50% and most preferably about 35% to 45%. The same good blue reflective color on the glass side is obtained in an IG unit.

Examples

The following example of coated article was made according to this invention. For the example, a coating shown in Fig. 1 was sprayed onto a 6 mm thick transparent glass substrate and had the next stack of layers from the glass substrate facing out (the silicon nitride layers). doped with approximately 2% Al):

Thickness layer (nm)

Glass substrate (6 mm)

SiN (5) 85 nm

NiCrN (7) 12 nm

Ag (9) 5 nm

NiCrN (11) 9 nm

SiN (13) 50 nm

In coated form, without any tempering and measured monolithically, the coated article of this example had the following characteristics:

Example 1 (monolithic, pre-HT)

Feature Example 1

T ^vis (or TY) (transmissive): 39.7%

a * ^t : -3,6

b * ^t : 1.9

R ^g Y (glass side): 21.4%

a * ^g : 0

bb * _g :: -17.2

R ^f Y (side of the movie): 12.7%

a * ^f : 13.3

b * ^f : 14.6

Resistance of the sheet (R ^s ): 7.7 ohms / square

Emissivity (normal): 8.7%

The coated article of the Example was subsequently treated with heat treated (heat treated-HT) for thermal tempering in a tape oven at about 620 ° C for about 9 minutes and 30 seconds. After this thermal treatment, the coated article had the following characteristics:

Example 1 (monolithic, after HT)

Feature Example 1

T ^vis (or TY) (transmissive): 40.3%

a * ^t : -3,5

b * ^t : 2.2

R ^g Y (glass side): 18.5%

a * ^g : 0.8

b ^g : -19.2

R ^f Y (side of the movie): 11.0%

a * ^t : 13.4

b * ^f : 14.7

Resistance of the sheet (R ^s ) 6.2 ohms / square

Emissivity (normal): 7.1%

The coated article of the example was then placed in an IG unit as shown in Fig. 2, so that the low emission coating was on the surface No. 2 of the IG window unit.

Although the invention has been described in relation to what is currently considered the most practical and preferred embodiment, it should be understood that the invention is not limited to the embodiment described, but on the contrary it is intended to cover several modifications and equivalent arrangements included in the scope of the appended claims.

Claims (9)

A coated article that includes a multilayer coating (3) supported by a glass substrate (1), the coating (3) comprising at least the following layers from the glass substrate (1) outwardly: a first layer (5) ) comprising silicon nitride; a first contact layer (7); an infrared (IR) reflecting layer (9) located on and directly in contact with the first contact layer (7); a second contact layer (11) located on and in direct contact with the IR reflecting layer (9); a dielectric layer (13); characterized in that the coated article has a reflective color value of the glass side b * of -15 to -25, wherein the first layer (5) comprising silicon nitride has a thickness of 72.5 to 110 nm, and wherein the coated article has a value a * of reflective color on the glass side of -4 to 4 and a value R ^g Y of visible reflectance on the glass side of 15 to 30%, where the first contact layer (7) comprises Ni and / or Cr, the infrared reflecting layer (9) comprises silver, the second contact layer (11) comprises Ni and / or Cr and the dielectric layer (13) comprises silicon nitride, and wherein the coating (3) includes only one Ag-based layer which is the IR reflecting layer (9), and wherein the first layer (5) comprising silicon nitride is in direct contact with the glass substrate (1), and where the coating (3) consists practically in the mentioned layers. 2. The coated article of claim 1, wherein the first layer (5) comprising silicon nitride has a thickness of 75 to 105 nm, and the coated article has the following reflective color values on the side of the glass: a * from -3 to 3, and b * from -16 to -23. 3. The coated article of claim 1, wherein the first layer (5) comprising silicon nitride is 80 to 95 nm thick, and wherein the coated article has the following reflective color values of the glass side: a * from -2 to 2, and b * from -17 to -22. 4. The coated article of claim 1, wherein the coated article has a laminar resistance not greater than 10 ohms / square and a visible transmission of 30-60%. 5. The coated article of claim 1, wherein the coated article is an insulating glass window unit (insulating glass - IG). 6. The coated article of claim 1, wherein at least one of the first and second contact layers (7, 11) comprises NiCr. 7. The coated article of claim 1, wherein each of the first and second contact layers (7, 11) comprise NiCr. 8. The coated article of claim 1, wherein one or both of the first and second contact layers (7, 11) comprises a NiCr nitride and wherein the coated article is thermally annealed. 9. The coated article of claim 1, wherein each of the first and second layers (5) comprising silicon nitride further comprise aluminum.